Laser ranging refers to measuring a distance with laser as a light source. According to working manners of the laser, laser ranging can be divided into continuous laser ranging and pulsed laser ranging, wherein the principle of the pulsed laser ranging is that the laser emitted by a ranging apparatus is received by the ranging apparatus again after being reflected by a measured object; meanwhile, a reciprocating time of the laser is recorded by the ranging apparatus. Therefore, a distance between the ranging apparatus and the measured object equals to half of the product of the speed of light and the reciprocating time. That is, the distance can be derived from the equation L=ct/2, where L is the distance between the ranging apparatus and the measured object, c is the speed of light, and t is the time for the laser to reciprocate once between the ranging apparatus and the measured object. Since the speed of light c is about 3×108 m/s, when measuring a shorter distance, time t is very short and hard to be measured precisely, thereby causing poor measuring precision of the ranging apparatus. Therefore, there is an urgent need for a ranging apparatus with high measuring precision in the art.